Just a note that the verification error shows up for both Blink and the bootloader uploads:
avrdude -p m2560 -P com4 -c avrisp -b 19200 -v -e -U flash:w:Blink.cpp.hex -U lock:w:0xCF:m
avrdude: Verification error.
avrdude -p m2560 -P com4 -c avrisp -b 19200 -v -e -U flash:w:stk500boot_v2_mega2560.hex -U lock:w:0xCF:m
avrdude: verification error.
Cheers!
Edit: Just noticed that pin13 LED is flashing when the board is powered, since loading the bootloader.. So it's possible that I can use the chip via ICSP programmer, without the USB working. Will look into this further, since it didnt seem to flash with just the Blink sketch uploaded.